Sleeping with a heater or blower on? Health risks you must know

The warmth of a heater or blower in the cold winter nights feels comforting, but hidden behind this seemingly ‘harmless’ habit are a number of health risks. From respiratory to sleep issues, studies have shown that these devices can bring about a number of complications and in rare cases can even be life-threatening. Understanding these factors and up to what extent sleeping with a heater or blower is safe is important to maintain precautions. Here are the health risks you must know:

Using a heater or blower can interfere with the indoor air, and
Several research reviews and studies on indoor environments also show that low relative humidity in heated indoor spaces is associated with increased dryness, respiratory irritation, and airway discomfort.
The dry indoor air can impair defence mechanism by drying out the mucus membranes, making one more prone to irritation, sore throat, and coughing.

The body needs to maintain an optimal temperature for deep, restorative sleep. While heaters and blowers provide warmth, they can interfere with this natural cooling process. Overheated rooms can make it harder to fall asleep, cause frequent awakenings, and reduce overall sleep quality.
​Studies on indoor climate and sleep indicate that both temperature and humidity influence sleep efficiency. Rooms that are too warm or too dry, common when using heaters overnight, are linked to fragmented sleep, lighter sleep stages, and reduced restorative rest.
This situation can feel extra uncomfortable for people with pre-existing sleep issues.

Research on indoor air quality shows that heating systems and poor ventilation contribute to higher airborne particulate matter.
A study in heated indoor environments found that occupants were more likely to experience coughing, sneezing, and respiratory discomfort, particularly during the winter months when heating is used extensively.

According to a January 2025 report published in the Kashmir Observer, doctors in Kashmir issued warnings about the dangers of using unvented gas heaters in closed spaces, noting that toxic combustion byproducts like carbon monoxide can accumulate silently and pose a deadly risk, especially while sleeping.
This is a major issue in fuel-burning heaters. Such heaters produce carbon monoxide (CO), a colorless, odorless gas that can accumulate in poorly ventilated rooms. Even low-level exposure to CO overnight can lead to headaches, dizziness, nausea, and fatigue, while higher concentrations can be life-threatening.